Recently, partly due to economic circumstances, it has become customary to package and sell a designated product such as fertilizer granules, wall plastering materials, instant ready cement, and the like, in plastic bags which are contained within cardboard boxes. The advantage of this combination is that the boxes are relatively inexpensive and reinforce the bag against handling abuse so that the bag can be of a thinner gauge less expensive plastic material than would be the case if the bag with contents were sold without a protective box. The bag in a box combination is a direct inexpensive substitute for plastic pails.
A difficulty with using plastic bags in boxes is that a complex procedure is required to seal the neck of the bag after the product has been dispensed into the bag, and then tuck the gathered neck neatly into the box so that the flaps at the top of the box can be glued together. On a full shift basis, it is usually possible for a human-being to twist-tie six or seven bags per minute. Not only is this labour intensive work, but it is also mind-numbing. It would be advantageous if the bags could be sealed at a faster rate, for example, 30 bags per minute, which would be more in line with the package speeds of conventional packaging conveyor systems.
The applicant is aware of the following references or patents which teach or disclose potentially relevant apparatus and processes for sealing loaded bags.
U.S. Pat. No. 4,364,511 discloses a tube of film material that is used to enclose food. The tube has a closure tie with a suspension lop. The enclosure tie includes a knot lying in a recess in the pleated tip of the film. The recess in which the tie is located is formed by softening the tube by heating, for example, with warm air, IR radiation, ultrasonic means, by previously heating the tie filament, or by treating the film material with solvents or softening agents. Equipment is also described to perform the process.
West German Patent No. 28 16 310 PS discloses a device for tying-up open bags of similar objects.
European Patent No. 0,010,937 discloses an apparatus for knotting the mouths of flexible packaging materials.
European Patent No. 0 132 715-A2, Poetz, B., discloses a closure which has a degassing valve.
European Patent No. 0 045 775, Houlberg, J.P. discloses an injection moulded bag closure.
European Patent No. 0 009 987, Debenham, M. et al., discloses an easy opening closure with a resealable pressure releasing device.
Verpackungsberater (1983) No. 8,487 discloses a binding machine that can be used for widely differing applications. Reference is made to a pallet binder, pallet releasers (strapping cutters), tunnel binders, a collar binding machine, a binder for flowers and vegetables as well as a standard automatic Type P machine.
Food Flavourings, Ingredients, Processing and Packaging, 1985, 7, 2-11, discloses an apparatus for Tetra-Pak.TM. packaging that cuts blanks from a jumbo roll seals the bottom and side (by hot air), and fills the seals up to 6000 gable-top cartons/h before replenishment with a new roll from the incorporated magazine is necessary. RC 7 and RC 4 machines are on the market with roll feed attachment, and RC 7 R-machines are adjustable for gable- or slate-top cartons. Another Tetra Pak innovation is a pull-tap opening - a sealed pear-shaped punched hole, airtight until removal of a covering A 1 pull-tab, with a small plastic strip attached to the pouring edge, for its 25, 200 and 250 ml aseptic cartons.
Emballage Digest, 1984, No. 277, pages 184-188, discloses an impulse welding machine; new PE films, LDPE canisters with incorporated handles, injection moulding, MB 600 film for wrapping confectionary boxes; light plastics pallets; canisters for chemicals; a Cubitainer.TM. for liquids; an Akylux display package; shrink film machines; injection machines for producing plastics corks; packaging of liquids or pasty products in bags; and foam packaging.
Australian Packaging, 1984, 32, (4) 22 describes a new twist wrap material, namely Hiblon.TM., an unaxially oriented polyethylene film based on the T-die extrusion method developed by Mitsui Toatsu Chemical Co. A table compares the properties of Hiblon with moisture proof cellulose and in particular the twist properties by a twist retention test. Special twist wrapping machinery has been developed to work at speeds of up to 1200 pieces/min. for hard sweets.
Emballage Digest, 1984, 26,(284), 119-121 discusses inviolable metal and plastic closures for barrels (Tri-Sure.TM. and Tab-Seal.TM.) and Sorfim.TM. cases - decorative presentation packaging for one or more luxury goods.
Verpackungs-Rundschau, 1984, 35, (11), 1536, 1537 discloses a method of injecting Plastisol.TM. onto polypropylene closures. The special sealing compound in the lid is heated in a continuous oven and then brought to the required temperature by microwave heaters. The plastic closure is not further heated at the same time. An extensive range of equipment achieves the desired levels of performance. Also described is a Daramelt.TM. system which enables other plastics, such as PE, to be used: These seals do not require any further treatment and the production of foamed seals is also possible. The process is also suitable for the packaging of food.
Emballage Digest, 1984, No. 276, 110, 112, 115, 116, 118, 120, 122-126 discloses automatic gluing of plastic pots; single material closure for mineral water; load securing with hotmelt; a new banding machine; machines for adhesive taping of boxes; hotmelt application systems; electric stapler and nailer; bands for retail packs; new closing joints with expanded PE and barrier films; welding of metal seams by polyamide hotmelts; and closing of cardboard packs.
Australian Packaging, 1983, 31, (11), 12 describes a new system of packing for the safe transportation of electronic apparatus, computers and precision instruments. The containers are lined with an inert, anti-static flexible foam cushioning material. An additional feature is the inclusion of a plastic locking device.
Emballage Digest, 1983, 25, (273), 24-30 discloses a plastic reclosable lid for cardboard packages containing instant drinks powder; PVC tear-resistant films for easy-to-open thermoformed packs; and biaxially-oriented hollow bodies.
Verpackungs-Rundschau, 1983, 34, (11), 1232-1233 describes a new type of PE for the production of packaging materials and packages: rigid, distortionfree, shock-resistant containers; large storage and transport containers; small transport cases and storage containers, and shock-resistant blown films for detergent containers.
Holz-Zentralblatt, 1984, No. 16,231 discloses flexible bands made of polyester resin which serve to secure pallet loads or bundles with trimmed timber and plates. For sealing the band is knotted, tensioned, tied or wedged.
Fixed spoked gear-wheel-like tape mechanisms are available on the marketplace and manufactured by companies such as 3M Corporation of Minneapolis, Minnesota.